for example, when i drap a rmvb file onto smplayer's window tab on the task manager(taskbar), it is expected that the smplayer should be activated and then i can drop the file into its window and play it. but it didn't be activated.
the same thing happens to konqueror.
when drap a mp3 file, the same thing happens to amarok.
so i think its not related to dolphin nor smplayer.
i think its related to KDE. it seems work well before i upgrated KDE from 4.8.5 to 4.9.3, but i dont remember well exactly.

---
openSUSE 12.2
dolphin 2.1
KDE 4.9.3
smplayer 0.8.1

I don't think that was ever possible.
For now you'll have to wait for the application to focus.

Bug #212081

I was going to post a topic with the similar content.

When I move a file (e.g. subtitles or mp3-file) on vlc media player (or some other program) it just does not focus on it. It does not matter how long I wait.

Please, add such function (that, at least, the program will focus), as it is present in Windows(!) and is very useful, when adding subtitles to a movie or a song to the playlist etc.

This function is just missing (Kubuntu till 2012.10 with newest updates (KDE 4.9.3) and I don't remember it working on the previous versions.

Please, add it.

Can you please clarify exactly the behaviour you are after here?
I observed the following:
- If a drag is initiated, then the target application is hovered over in the Task Manager, the target application will be given focus
- If a drag is initiated, but the drag is just made directly to the (already visible) target application, then no change in focus will occur.

Is it the 2nd behaviour you are requesting here?

Dear bcooksley,

after downloading the latest updates of January 3rd, 2013 for Kubuntu 12.10 64bit it looks like this bug has been solved. Namely - focusing of application from taskbar works.
Namely: when I drag a file to an application, which
- is minimized in task manager or
- the application is hidden behind other applications, so the one can not see the needed window but just an icon with description in task manager,
than focusing is working.

That was the requested behaviour from my side, which now works!
Thanks!